The AUSubaru.com.au Forums

hi all

i recently got a 2.5inch sports exhaust for my l-series wagon, from the y-pipe back.

Can they make the car guzzle more fuel? it seems i am only getting about 350-375km out of a tank, compared to before where i was getting 420-440km!

alex

Hey

From my previous experience from getting an exhaust upgrade is that you like the sound/note so much that you tend more to put ya foot down harder just too hear it. I'm getting my exhaust upgraded in the new year and expect a higher fuel bill at least for the first month..

2006 The year of the subaru upgrade..

Webber, liftkit, exhaust, 14"rims and tyres, Electronic dizzy, mmmm and much much more

i have a few theories, they may not be accurate but i think they apply to me, i have a custom 1.75" equal length Y pipe that goes into a 2 inch straight through system, a hot dog & a turbo muffler at the back

1. Could it be that because the exhaust flows more freely, you are more inclined to rev it out for longer in each gear, which would mean more fuel

2. The better flow exhaust means more air flow through the engine, more air through the engine means more fuel as well

3. You just love to hear your exhaust note so sub-conciously you rev the guts out of it

(i think they all apply to me, especially No. 3)

hehehe

i think your all right, now i think about it, the rexxy sound probably does make me drive harder!

Especially when you flatten it and it goes nowhere!(and that gravel circlework doesnt help!)

Alex

Hello Hello,

I got a mate who's dad builds exhausts. He tells me to be careful with an exhaust up grade. Your trying to eliminate any points in the system where it is restrictive or turbulant. Your exhaust is meant to be like a chimney, when it gets hot it helps draw out the exhaust gases, turbulance restricts this and the engine has to put in a little more work...

Basically 90subiewgn, i think your experincing increased fuel consumption due to turbulance in the exhast, going from the standard size pipe to the larger size. If you have your old exhaust and some time to play around, whack it back on and see if your fuel consumption goes back to how it was...

I've been recommended the best and easiest way to get better performance with a nice note on the cheap is to put a set of straight through sports mufflers and if you can be bothered a sports straight through cat converter to fit the original pipe size...

I too will be playing with my exhaust in the near future... hope to post something on the topic... I'm thinking of making the Y pipes the same length with the cat converter straight after the Y joint, all standard diametre pipe with the straight through mufflers. If anyone has done this and have some pics of it, i'd love to hear from you...

Hope this is some help to you.

Cheers

El Freddo
(aka Bennie)